Given new understandings in radiation biology, there is a real possibility that people in Japan exposed to low-dose nuclear radiation in a geographical perimeter outside of the immediate area of radiation leakage near Fukushima, Japan will actually live longer and healthier lives.

This pre-drawn conclusion is made in the light of recently published studies that confirm the biological phenomenon known as hormesis, explained as exposure to mild biological threats that trigger the body’s internal antioxidant defenses and speed repair of damaged DNA.

This is a follow-up report pertaining to human nuclear radiation health hazards posed by the tsunami/earthquake-induced nuclear plant radiation leaks in Fukushima, Japan which I first reported in March of 2011.

There is also newly published data from animal experiments showing low-dose radiation exposure, typical to what a human would receive from a screening x-ray for lung cancer, may actually activate the body’s defenses against cancer, which corroborates with the observed decrease in human lung cancer mortality reported by The National Lung Screening Trial Research Team study. Another recently-published animal study also corroborates the idea that low-dose radiation exposure may reduce cancer risk.

How much radiation produces hormesis?

We now have accurate measure of the amount of radiation exposure to human populations in Japan.

For reference, radiation biologists measure radiation exposure in millisieverts (mSv), an international unit of radiation dosage. (One sievert is equal to 100 rems, which is a dosage unit of x-ray and gamma-ray radiation exposure; one millisievert is 0.1 rem.)

According to a report published in Nature magazine, most residents of Fukushima prefecture received between 1–10 millisieverts (mSv) in the first year after the accident. Those in neighboring prefectures received between 0.1–10 mSv, and the rest of Japan received between 0.1–1 mSv. These levels are said to be “well below the government’s maximum recommended dose of 20 mSv and will cause a minimal increase in cancer risk.”

As David Brenner, a radiation biophysicist at Columbia University in New York, explains, a dose of 5 mSv would be estimated to lead to one excess cancer per 5,000 people exposed. Given that roughly 2,000 of those 5,000 people are going to develop cancer anyway, this is a tiny increase in risk, and Brenner emphasizes that the uncertainties in his calculations are high.

But that radiation exposure levels and subsequent future cancer cases were over-estimated may not be the biggest part of the story emanating from Fukushima.

Biologists have now identified the actual gene (Nrf2) pathway that activates protective internal antioxidants (hormesis) as well as the natural molecules that activate this gene pathway (resveratrol, curcumin, green tea), which by the way are only protective at low dose (but above dietary intake levels).